COMPACT LAYOUTS IN SALESFORCE

Compact Layouts:

--> Compact layouts display a record's key fields at a glance in salesforce classic, mobile app(salesforce 1), lightning experience. 

Note : You can select and prioritize up to ten fields for the compact layout, but the number of fields that display may vary based on the device's screen, which record page is being viewed, and the permissions of the user.

--> If we want to see the fields in records in salesforce classic, mobile app(salesforce 1), lightning experience we have to scroll down to search for the particular field which is fed up with this by many users, because of this we can use compact layout to display a record's key fields at a glance.

Points to remember :

--> Compact layout supports all field types except text area, long text area, rich text area, multi select picklist.
--> Each record type can have only one compact layout assigned to it, compact layout can be assigned to multiple record types.
--> A compact layout can only contain field from its object including a formula field that is a cross object reference to another object.